Mass production of Positrons (Anti-matter)

originally posted by: Zaphod58
a reply to: chr0naut

The Manhattan Project began in 1939, with it really hitting its stride in 1942. Most of the cost was building the factories to build the fissile material, but they had over 30 sites across three countries working on the bomb design and production. They spent three years designing the weapon, as well as refining the fissile material before the first detonation in 1945. The work on different types of bombs had been going on for at least two years before the types were detonate. The designs took at least two years to perfect. You don't detonate one type of nuclear bomb, then suddenly go "hey, this works better" and change the design and have one in a couple of days.

What does history show?

The first paper on nuclear fission was published in January 6,1939 by Otto Hahn, a German living in Switzerland. He was awarded the 1944 Nobel prize in Chemistry for that work.

There may be reason to believe that Werner Heisenburg, the leader of the German project to develop a nuclear reactor, was sabotaging the process from within, to delay it as long as was possible. Definitely after the Hiroshima bomb, he was asked by his fellow researchers how could the Americans have built a bomb with such a low mass and, without reference to any other figures or texts, he wrote out the equation in front of them and correctly derived the supercritical mass of the Hiroshima bomb. I.e: he had known all along.

You see the A-bomb designs reflect the equations and the equations were known years before Manhattan Project had begun.

The biggest issue was that tens of thousands of chained centrifuges (and even later & higher volume isotopic separation devices) take years to yield enough weapons grade mass.

The story that it takes years of complex calculation and careful design to produce an atomic bomb is part of the non-proliferation process and a myth.

If you have enough weapons grade to make two slightly subcritical (-5 cent, say, for Pt) masses, a lift shaft of a city building and some concrete for mass to hold the 'halves' together, you have a bomb.

You could add some linings of neutron reflective material around the masses (like steel, graphite, beryllium or tungsten carbide), bringing the parts of the physics package closer to criticality and maintaining supercritcality for longer.

... and there are other, cheap & quite easily sourced components that would make for a more reliable detonation.

None of this is particularly secret.

No major equations, advanced design or even explosive required.

a reply to: chr0naut

That they were developing the bombs for several years, and detonated them about the same time. That's part of the Manhattan Project history. They didn't take several years to get the fissile materials, and a few days to design and build the bombs. You can repeat it all you want, but history shows that multiple countries spent multiple years on design and production of the weapons.

a reply to: Bornsecrets

OK you seem confused positrons are not anti matter. They are produced thru beta decay. Your confusion comes in because science considers the positron the anti particle for an electron. They simply mean it's opisit. There is an anti proton that would be found in anti matter. The only effective way to make anti matter is a collider.

Then it's it's small amounts a couple of particles at a time. And the cost is rediculous like in the millions of dollars for a couple of particles. So in other words no chance of using as a weapon of any type.

originally posted by: dragonridr
a reply to: Bornsecrets

OK you seem confused positrons are not anti matter.

Positron

The positron or antielectron is the antiparticle or the antimatter counterpart of the electron.

Then it's it's small amounts a couple of particles at a time. And the cost is rediculous like in the millions of dollars for a couple of particles. So in other words no chance of using as a weapon of any type.

No doubt that was the case and maybe still is (see my earlier post in this thread about that), but what's getting some people excited are claims that the cost of making and storing positrons has the potential for drastic cost reductions. Even if that's true which it very well may be, reducing the cost even by 1000x would probably still be too expensive compared to the cost of weapons we already have.

a reply to: Arbitrageur

You have a PM

a reply to: Arbitrageur

In quantum field theory electrons and positrons don't exist as particles at all. A positron is a hole in a Dirac sea. In quantum field theory a positron cannot be a point charge. The best way to look at it is simply an area where there is no electron field.

old TV's (CRT tubes) used them as well.

I've been following along and I was paying attention when the Korean event happend. It came up that day on one of the email notifications I used to subscribe to, as a seismic event and or possible nuclear detonation.
At the time I thought for sure we were involved in some fashion, but I wasnt sure how, an energy weapon would have been the most likely scenario.
Now, I more or less speed read this thread, and did not see any reference to the NK amunition train that is the official cause of the explosion or Dear Leader's train being in the station minutes before.

We were involved, but it is not an antimatter bomb, but a charged particle beam.
In the months before the incident the, USAF launched one of the largest payloads they ever have.
It was so secret that even the senate intel. committee was not privy to the payload's actual purpose. At the time it was thougth to have been a KH series sat.
In 07, I found a patent granted to the DOD, via one of the labs, but one I was not familiar with, for a signal filter for a "directed energy device". It went into pretty amazing detail, for what one would think is a secret program, about the devices overall purpose.
The device, through the use of directed charged particles can activate high energy materials, ie make explosives explode. The patent paperwork talked of the device being suitable for use on the ground, from the air or orbit, even materials buried up to a certain depth, which was not disclosed.
It also stated the device was originally designed to detect and explode hidden ordinance, such as ied's.
Around 2008ish, I remember reading of a test of a hummer mounted device, that was succesful, but I really have not heard anything since.

a reply to: Bornsecretsdoes a pet scan not make positrons or does it just use ones already in nature ?

PET uses a radioactive tracer isotope, Fluorine-18 which decays via positron emission (beta+ decay). Fluorine-18 is synthesized using an accelerator.

The primary signal you look for in a PET machine is coincident back to back gammas each with 511keV energy which you detect with a segmented ring structured detector.

a reply to: Zaphod58

Thank god for this too!!

Also, that would be insanely surprising for nooks to have such a quick turnaround cycle when 50+ years after the first AR15 was produced nothing has substantially beaten it's basic design by a margin sufficient to dethrone it.

Firearms being like 7 or 8 orders of magnitude less complex and all...

Totally unrelated sidenote: nothing short of LSAT will dethrone it either considering that within the next 24 months you'll be seeing an updated (but still 5.56 chamber, peak pressure, and even100% legacy parts build compatible!) 62 grain cartridge that pushes 16 inch bbl guns way out past 600 meter ranges! Along with that the host of drop in parts that will be showing up will essentially take the gun itself so far beyond bullet proof that no one else will really have even a hope of competing.

a reply to: Bornsecrets

Check out your PM, dude

a reply to: SpeedFanatic

Would love to hear your thoughts on this topic.

a reply to: Zaphod58

Agreed. It takes less time now to replicate Trinity, but that isn't the goal. Reducing mass and diameter significantly for weaponization is not so easy and details aren't public.

Then, the modeling for radiation-coupled fusion implosion is far, far, more difficult, and requires a reasonably clean primary design (i.e. not Trinity) which gives the x-rays first well before the debris disassembles you.

Re Heisenberg: the way I heard it wasn't that he was sabotaging (after April 1945, only "some other Germans" were Nazis), he, and his team were wrong, and Fermi was right.

The plutonium breeding reactors weren't working so well, contrary to the theory. Heisenberg's team gave up and concentrated on heavy water---and the allies bombed the crap out of those factories so they never got far enough. Fermi figured out the problem wasn't the theory but the materials---the graphite was contaminated by some impurities which killed the reaction. Better quality graphite fixed it, and the plutonium breeding (Hanford) worked.

a reply to: mbkennel

Good to see you posting again. Any thoughts on the thread topic.

a reply to: BASSPLYR

Funny how Google seems to know everything.

aip.scitation.org...

That other country probably is China.

journals.aps.org...

This last paper seems to give a good overview of the physics and has quantitative estimates of the e+ yield.

Essentially fs lasers can accelerate some electrons to very high energy which then, when passing through matter, create secondary showers of particles. The kinetic energy of the high speed electrons is converted by passing through matter to rest mass of positron & electron pairs (plus obviously more electrons to conserve charge) which have lower kinetic energy.

The "element" that isn't an element might be a plasma? Something that you have some material control over more than taking nuclei as they are? The recoil against the nucleus is required to satisfy conservation of momentum. If there were some other way to satisfy conservation of momentum when a fast electron passed by, then that could also work to facilitate the decay of the kinetic energy into pair production. Cross section also scales substantially with higher Z nuclei.

Maybe something like this?

arxiv.org...

There they say explicitly scaling how gas targets can create more pairs at higher intensities.

Money quote: in a gas target, in certain parameter regimes,

a large fraction
of the pairs generated go on to produce additional
pairs, the reaction runs away and a cascade of antimatter
production ensues.

And not unsurprisingly, this process probably has been observed astrophysically decades ago, black holes & neutron stars.

Thinking about a phrase like "reaction running away"....wasn't something in Utah unexpectedly a whole bunch more sunburney than planned? Castle Bravoish? Like not taking into account QED?

By the way, the in orbit targeting of high explosives with charged particle beams (hard to imagine success on planetary scale because of magnetic fields, but whatever) is a potential strategy for ballistic missile defense---cause failures in the implosion explosives on warheads.

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a reply to: mbkennel

Edited TMI

a reply to: mbkennel

Hey you have a PM from me regarding sonething else.

a reply to: mbkennel

Edited TMI

a reply to: BASSPLYR

my inbox is empty, ATM